The present invention relates generally to vibratory conveying devices, and more particularly to a vibratory conveying apparatus having a selectively adjustable spring assembly which facilitates tuning of the apparatus for specific applications.
Vibratory conveying devices are employed in a wide variety of material-handling applications, such as for handling food products, particulate material, small parts, and other applications which do not lend themselves to use of belt-type conveyors. These types of conveying devices operate by creating vibratory motion in a bed-like conveyor trough, either by operation of mechanical or electromagnetic drives.
In a typical vibratory conveyor having an electromagnetic drive, one or more spring assemblies, typically comprising leaf springs, operatively support the vibrating trough of the device on an associated base which typically houses the electromagnetic drive. Reciprocating, vibratory motion is imparted to the trough by the electromagnetic drive, with the one or more spring assemblies of the device arranged to permit angular, vibratory movement of the trough. In this manner, material in the trough is conveyed as it is moved angularly upwardly during movement of the trough by the vibratory drive, with the trough then moved rearwardly beneath the material.
Several factors typically affect the vibrational operation of this type of conveying apparatus. The ratio of xe2x80x9ctrough side weightxe2x80x9d (the weight of the trough plus the material therein) to xe2x80x9cbase side weightxe2x80x9d (the weight of the supporting base structure) affects tuning of the apparatus, as does changes in the spring rate of the leaf springs which support the trough on the base. Operational tuning can also be effected by altering the xe2x80x9cair gapxe2x80x9d of the electromagnetic drive of the device, which effectively alters the vibrational stroke of the drive, typically on the order of 0.025 inches to 0.25 inches.
While the above techniques are well-known for tuning a vibratory conveying apparatus for optimal conveying efficiency, adjustment of weight ratios, air gaps, and spring rates have heretofore typically required that components of the apparatus be adjusted or altered, detracting from efficient tuning. Additionally, tuning techniques typically employed heretofore frequently require that a conveyor be especially configured for a given application, thus detracting from efficient manufacture of conveyors for varying applications.
The present invention contemplates an arrangement to facilitate efficient tuning of a vibratory conveyor by providing at least one adjustable spring assembly operatively connecting the base of the conveyor with an associated vibratory trough.
A vibratory conveying apparatus embodying the principles of the present invention is configured to include at least one adjustable spring assembly operatively connecting a base of the conveyor with the associated feed trough. By this arrangement, the effective spring rate of the adjustable spring assembly can be selectively varied, which permits efficient adjustment of the operational characteristics of the conveyor, including the conveyor stroke, without variation in the associated electromagnetic drive of the conveyor. This facilitates use of the conveyor for conveying differing types of material, and can even accommodate adjustment of the conveyor""s operating characteristics for accommodating variations in the frequency of the power supplied to the electromagnetic drive of the conveyor.
In accordance with the illustrated embodiment, a vibratory conveying apparatus embodying the principles of the present invention includes a base, and a trough, and at least one spring assembly which mounts the trough on the base for vibratory conveyance of material in the trough.
An adjustable spring assembly in accordance with the present invention can be provided in a variety of configurations, with each configuration facilitating use with conventionally structured vibratory conveying devices. In the illustrated embodiments, the adjustable spring assembly includes a lower arm connected to the base of the conveying apparatus, and an upper arm connected to the trough of the device. An adjustable spring element mounted between the upper and lower arms can be adjusted to selectively vary the spring rate of the adjustable spring assembly, thereby altering the vibratory characteristics of the trough, without adjustment of the associated electromagnetic drive. Use of an adjustable compression spring is presently preferred, with illustrated embodiments including an elastomeric compression spring and a coil compression spring.
In certain embodiments, the adjustable spring assembly of the present invention includes a stack of leaf springs, with the adjustable compression spring of the assembly positioned on one side of the leaf spring stack. In other embodiments, the adjustable spring assembly includes a pair of leaf springs, with the adjustable compression spring positioned between the pair of leaf springs.
In the illustrated embodiments, the trough of the conveying apparatus is mounted and supported by a pair of spring assemblies, with one of the assemblies being positioned proximally of the electromagnetic vibratory drive, and the other of the assemblies being positioned distally of the vibratory drive. In accordance with the present invention, the adjustable spring assembly can be positioned proximally of the drive, or distally of the drive. In a further embodiment, each of the illustrated pair of leaf spring assemblies is non-adjustable, with an adjustable spring assembly positioned between an upwardly facing surface of the conveyor base, and a generally rearwardly facing side wall of the conveyor trough.
Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.